How to make custom dynamic variable [Buy-Intent]

Summary:

Procurement contracts.

Customer requirement is to be able to make some custom dynamic variables to get specifics information like a, supplier (taxpayer identifiers, type, etc), item (type, category, etc) and PO Lines/Distributions.

Content (required):

I need to make some custom dynamic variables to get specifics information like a, supplier (taxpayer identifiers, type, etc), item (type, category, etc) and PO Lines/Distributions.

How can I do it?

The only way is like Java Methods (Using Procurement Contracts Doc: Examples of Creating Java Methods for User Variables) or there are another way?

Any help would be appreciated.

Version (include the version you are using, if applicable):